A battery includes, for example, an electrode assembly including a positive electrode, a negative electrode, and a separator, an electrolyte, and a battery case housing them. The battery case includes a case main body having a bottomed cylinder shape or the like and a sealing body that seals the opening of the case main body. For example, PTL 1 discloses a lithium secondary battery having a gasket that is located between a case main body and a sealing body and maintains the airtightness in the battery case.
FIG. 5 is a sectional view showing a conventional battery 50.
As shown in FIG. 5, the battery 50 includes a battery case 52 including a case main body 53 that houses an electrode assembly 51 and a sealing body 54 that seals the opening of the main body. A gasket 55 made of resin having elasticity is provided between the case main body 53 and the sealing body 54.